A superconducting tunnel junction x-ray detector with performance limited by statistical effects

Abstract

Tunneling of nonequilibrium quasiparticles excited by x-ray quanta in a nonsymmetric superconducting tunnel detector Low Temp.

X-ray Detection Performance of 100-pixel Superconducting Tunnel Junction Array Detector in the Soft X-ray Region

“…The average and standard deviation are 10.2 and 1.7 eV, respectively. These intrinsic energy resolutions are almost the same as the best values for Nb-STJ array [3,5], and 2-3 times of the best values for single pixel STJ detectors reported up to now [7,8]. Thus, we have succeeded in realizing an STJ array detector with a large sensitive area and good energy resolution.…”

Superconducting Tunnel Junction Array Development for High-Resolution Energy-Dispersive X-ray Spectroscopy

“…While the detector resolution of the 200 × 200 µm 2 devices is poorer than the resolution of smaller devices (LeGrand et al, 1998), it is still sufficient to fully separate the Ni L and the Fe L fluorescence from the strong oxygen K line centered at 525 eV. In many applications, it is desirable to trade off resolution for larger solid-angle coverage as long as the detector can handle the higher count rate.…”

“…In earlier experiments, our small 50 × 50 µm 2 devices showed an energy resolution between 4.6 and 8.9 eV FWHM for X-ray energies between 0.2 and 1 keV (LeGrand et al, 1998). The device discussed here is a linear array of four 200 × 200 µm 2 STJ detectors.…”

“…This comes at the expense of a lower maximum count rate around 500 counts/sec, because the relaxation of thermal devices back to their equilibrium is intrinsically slow (Wollman et al, 1997). STJ detectors offer a slightly poorer resolution of 15.7 eV FWHM at 6 keV (Verhoeve et al, 1998), although this may be improved if future devices employ superconductors with extremely low critical temperatures (Peacock et al, 1996;LeGrand et al, 1998;Kraft et al, 1998). However, STJ detectors can be operated at significantly higher count rates of the order 10,000 counts/sec (Frank et al, 1998b).…”

XANES, EXAFS and Kbeta spectroscopic studies of the oxygen-evolving complex in Photosystem II

“…Finally, the oxygen K-edge is only 100 eV lower in energy than the Mn L -edge; thus, superconducting energy-resolving detectors must be used to discriminate against the vast amount of oxygen Kα fluorescence that is present. 306 These problems are particularly challenging in view of the potential of Mn L-edge spectra to provide detailed information about the Mn atoms in the OEC. In many ways, Mn L -edge spectra are superior to Mn K-edge spectra, because multiplet calculations 307 can be applied to L -edge spectra which are sensitive to the number of holes in the 3d level, 308 the oxidation state of Mn, and the spin state of Mn.…”